Two or three stages gcc build?

Thomas Petazzoni thomas.petazzoni@free-electrons.com
Thu Sep 19 05:03:00 GMT 2013


Dear Khem Raj,

On Fri, 6 Sep 2013 09:59:34 -0700, Khem Raj wrote:

> > In the mean time, I've experimented a bit and actually implemented it.
> > The patch hasn't been merged yet in Buildroot, but it has been posted:
> > http://lists.busybox.net/pipermail/buildroot/2013-September/077344.html.
> > 
> > Don't hesitate to have a look and tell me what you think.
> 
> OK. The patch looks ok to me. one thing

After merging the patch, we got a report that it breaks SSP support,
see [1]. After investigation, depending on the architecture, the
__stack_chk_fail symbol maybe be part of the TLS (it's the case on x86,
but on ARM, for example).

However, since we're now only doing gcc-initial -> uclibc -> gcc-final,
and gcc-initial has no thread/TLS support, it breaks the build of
uClibc when SSP support is enabled (in such a case, uClibc is built
with -fstack-protector, which creates references to __stack_chk_fail,
but this symbol isn't available because we don't have TLS support).

Have you already seen this problem? What solution do you suggest?

Thanks!

Thomas

[1]
http://buildroot-busybox.2317881.n4.nabble.com/uClibc-fails-to-build-with-stack-smash-protection-td51478.html
-- 
Thomas Petazzoni, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com

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